mtd: nand: ifc: update bufnum mask for ver >= 2.0.0

mtd: nand: ifc: update bufnum mask for ver >= 2.0.0

BugLink: http://bugs.launchpad.net/bugs/1756978
[ Upstream commit bccb06c353af3764ca86d9da47652458e6c2eb41 ]

Bufnum mask is used to calculate page position in the internal SRAM.

As IFC version 2.0.0 has 16KB of internal SRAM as compared to older
versions which had 8KB. Hence bufnum mask needs to be updated.

Signed-off-by: Jagdish Gediya <jagdish.gediya@nxp.com>
Signed-off-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>